1. Field of the Invention
The present invention relates to a connecting element, specifically for sealing the gap between the wall of an outer pipe to which a branch pipe is connected and the wall of an inner liner pipe, at a branch opening extending through both inner and outer pipe walls.
2. Description of the Related Art
Pipe conduits which are in need of repair are nowadays increasingly restored or repaired in that a cladding in the form of a further pipe of a somewhat lesser diameter is inserted into the pipe conduit. This pipe shaped cladding ("liner") is inserted by means of recently developed techniques. It is necessary that the cladding must be provided after its insertion with suitable opening at those places where branch pipes are present with corresponding openings. Because the pipe conduits are generally not such opening are made by means of apparatuses which can travel through the pipe and are equipped with remote controlled cutting tools (roboter).
There is now the task to bridge or close off in a sealed manner the gap at the areas of connection between the branch pipes and the pipe wall of the later inserted inner pipe, which gap is present at every through opening between the inner and the outer pipe wall, such that on the one hand the contents of the pipe can not enter into the interstice between inner wall and outer wall and, in case that interstice is filled by material for a stabilizing (e.g. settable cement mortar) this filling material can not exit into the pipe.
It in fact is known to insert ring shaped hoses between two concentric pipes and to expand them in order to therewith provide a seal. Due to structural reasons these elements are not suitable for solving the present problem, among others because such an element could not be inserted at the desired location by the available apparatuses.
A known solution consisted of a sleeve of a rubber elastic material which can place itself onto the areas to be sealed due to its elasticity. The drawback of this which is shown in FIG. 2 of the drawings consists in that the element must be produced extremely precisely in order to display the desired effect. In spite of the elasticity of the element tolerances can be taken only within narrow limits. Additionally, the sealing effect would be nullified under the pressure of the filled in material in the interstice of the pipe.